On Mars, Ice and Salt

An electrical short in the Phoenix Lander's mechanical arm delayed its exploration of the Martian north pole last week, but new photos on Saturday revealed that the spacecraft's thrusters had uncovered a large patch of ice, which is exactly what scientists hope to sample and analyze.

But the planet may be too salty to support life as we know it. At least that is the conclusion of a study of minerals near the Martian surface in the Meridiani plain. The rover Opportunity discovered ancient deposits of magnesium sulphate there that appear to have been left behind by salty water.

Even beyond our system, there may be many Earth-like planets in the cosmos. A four-year study of 400 stars found that as many as 30 percent possess close-in, relatively small planets with some Earthly characteristics.

And an amateur stargazer has been credited with discovering the fastest rotating natural object in our solar system. The space rock, as big as a house, spins once every minute. It zoomed past earth in April.